Optical fiber including a diffuser portion and continuous sleeve for the transmission of light

ABSTRACT

A novel optical fiber, and a method for its production, having a diffuser portion and continuous unitarily-constructed outer sleeve, which is adapted for the transmission of light to a treatment locale. More particularly, a medical instrument has an optical fiber including a diffuser portion at a distal end wherein an alignment sleeve for the optical fiber extends uninterruptedly in a single piece from a connector for a laser light source to at least the distal end of the core of the optical fiber.

This continuation application claims priority to U.S. patent applicationSer. No. 09/785,571 filed Feb. 16, 2001, which is now a U.S. Pat. No.6,522,806.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates, in general, to a novel optical fiberhaving a diffuser portion and continuous unitarily-constructed outersleeve, which is adapted for the transmission of light to a treatmentlocale. More particularly, the invention relates to a medical instrumentwith an optical fiber including a diffuser portion at a distal endwherein an alignment sleeve for the optical fiber extendsuninterruptedly in a single piece from a connector for a laser lightsource to at least the distal end of the core of the optical fiber.

Currently, surgeons frequently employ medical instruments whichincorporate laser technology in the treatment of benign prostatichyperplasia, or as commonly referred to as BPH. BPH is a condition of anenlarged prostate gland, in which the gland having BPH typicallyincreases in size to between about two to four times from normal. Thelasers which are employed by the surgeons to treat this condition musthave durable optical fibers that distribute light radially in apredictable and controlled manner, and must also be capable of bendingwithout breaking, whereby small-sized or slender optical fibers offer anadditional advantage to the surgeon.

An optical fiber which is adapted to be employed for this purposetypically contains a glass core surrounded by cladding, a buffer layer,and an outer alignment sleeve. The cladding protects the inherentlyweaker glass core by imparting a mechanical support to the core. Thecladding also ordinarily possesses an index of refraction which is lowerthan that of the core in order to block light transmitted through theoptical fiber from emerging radially from the core. Although opticalfibers which are utilizable for such surgical procedures and treatmentsare widely known and successfully employed, the present invention isdesigned to provide further significant improvements and advantages overthe state-of-the art.

2. Discussion of the Prior Art

An optical fiber with a diffuser portion for diffusing light emitted atan end thereof is disclosed in Esch U.S. Pat. No. 5,754,717 as shown inFIG. 1 of this application, which patent is commonly assigned to thepresent assignee, and the disclosure of which is incorporated herein byreference. There is illustrated an optical fiber leading end 10 having adiffuser portion 12 comprised of the stripped core of a typical opticallaser, an optical coupling layer, and an outer or alignment sleeve 14.The optical coupling layer, replacing a part of the cladding and thebuffer layer of the optical fiber, has an index of refraction exceedingthat of the core so as to draw the light out of the core usingwell-known physical principles. The alignment sleeve is abraded, orroughened, in order to conduct light from the optical coupling layer tothe exterior, while heat staking or ultrasonic welding is used to applyor attach the portion of 14 a of the outer sleeve 14 covering thediffuser tip to a further separate portion 14 b of the sleeve locatedtowards the end of the optical fiber.

In essence, the method of forming the diffusion portion of the opticalfiber illustrated in FIG. 1 representing the Esch patent, necessitatesthe presence of a weld joint 16 near the distal end of the remainingcladding. Producers of optical fibers with diffuser portions intendedfor this or similar surgical purposes are required to ensure an adequatemechanical strength of the fiber for the intended application, and inwhich the weld joint can result in a stress concentration reducing thestrength of the optical fiber. It is also possible that silicone oradhesive from the optical coupling layer may contaminate the area of thesleeve junction during assembly, thereby weakening the weld joint. Whilethe weld joint is deemed to be of adequate strength for most surgicalapplications, designers would like to use smaller-sized optical fibers.As the diameter of optical fibers become smaller, the degradation instrength of the optical fiber caused by the presence of the weld jointbecomes more pronounced and resultingly important. The smaller diffuserscan readily break or become detached at the weld joint; whereas the weldscam at the weld joint can catch on instruments and interfere with themedical procedure, thereby creating a nuisance, if not an operatingdanger for the surgeon.

Other publications which disclose various constructions and types ofoptical fiber arguments which may be applicable to surgical proceduresand treatments employing laser illumination are widely known in thetechnology.

Anderson et al. U.S. Pat. No. 5,814,041 pertains to an optical radiatorand laser fiber in which the distal or leading end sleeve portion of theoptical fiber is attached to a second sleeve portion so as to form aweld or contact seam therebetween.

Evans et al. U.S. Pat. No. 5,802,229 discloses a fiber optic radiationsystem which, similar to Esch, does not provide for a continuous,unitarily constructed outer sleeve for the optic fiber.

Bruce U.S. Pat. No. 5,534,000 discloses a laser fiber apparatus whereinthe leading or ablation end of an optic fiber is provided with arelatively short outer tube element so as form an essentiallynon-continuous sleeve surface providing a seam-like joint or step.

Similarly, Doiron et al. U.S. Pat. Nos. 5,269,777 and 5,196,005; andMcCaughan, Jr. U.S. Pat. Nos. 4,693,556 and 4,660,925, disclose varioustypes of optical fibers with light diffusers or similar structures;however, none of which evidence the continuous single-piece outer sleeveof seamless length as provided for by the present invention, nor themethod of forming thereof.

SUMMARY OF THE INVENTION

Accordingly, the design of an optical fiber with a diffuser portionincluding an outer sleeve wherein the weld joint is eliminated is highlyadvantageous in constructing the sleeve of the optical fiber extendingas one continuous, uninterrupted or unitary piece from the connector fora light source to the distal end of the core.

Pursuant to the invention, a medical instrument comprises a source for alaser light wherein an optical fiber with a diffuser portion at itsdistal end has the outer sleeve of the optical fiber constituted of acontinuous unitarily-constructed tube extending from the connector forthe laser-light source to at least the distal end of the core in theoptical fiber. The sleeve of the optical fiber also contacts andsupports the optical fiber at the leading or light emitting distal endthereof.

Accordingly, it is an object of the present invention to provide amethod of producing an optical laser fiber arrangement in which theouter tubular sleeve encompassing the fiber core is of a continuous,unitarily constructed and seamless tubular structure.

Another object of the present invention is to provide a medicalinstrument incorporating an optical laser fiber produced in accordancewith the inventive method for forming the optical fiber portion of theinstrument.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference may now be made to the following detailed description ofpreferred embodiment of the invention, taken in conjunction with theaccompanying drawings; in which:

FIG. 1 illustrates a longitudinal sectional view of an optical fiberutilizing the diffuser portion as shown in the Esch U.S. Pat. No.5,754,717, representative of the prior art;

FIG. 2 illustrates a schematic representation of a laser deviceutilizing the optical fiber pursuant to the present invention;

FIG. 3 illustrates a diagrammatic perspective view of an optical fiberassembly incorporating an embodiment of the present invention;

FIG. 4 illustrates a longitudinal sectional view of the inventiveoptical fiber utilizing a diffuser portion, showing as represented fromthe interior to the exterior thereof, a core, an optical coupling layer,and an outer sleeve contacting the core distal to the diffuser portion;

FIG. 5 illustrates a fragmentary sectional view showing the annulusmaterial containing a light-scattering component;

FIG. 6 illustrates a longitudinal sectional view showing the annulusassembled to the core prior to implementing the tipping step in anoptical fiber utilizing the inventive diffuser portion, and

FIG. 7 illustrates a longitudinal sectional view of an embodiment of anoptical fiber utilizing the inventive diffuser portion showing, asrepresented from the interior to the exterior, a core, an opticalcoupling layer, and an outer sleeve contacting the core distal to thediffuser portion.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring in detail to the drawings, for purposes of this description,“proximal” refers to a section on the inventive optical fiber 28 closerto a source of light energy 22, and “distal” refers to a section on theoptical fiber which is further away from the source of light energy 22.

Illustrated schematically in FIG. 2 is a medical instrument 20 fordiffusing light from an optical fiber 28. The medical instrument 20includes a source of light energy 22, preferably a laser; and whereinthe optical fiber 28 connects into the source of light energy 22 throughthe intermediary of a connector 18 which is attached to a connectionport 24 leading to a diffuser portion 19 of the optical fiber. A typicalconnector and connection port of this kind which can be utilized for themedical instrument 20 is described in Evans et al. U.S. Pat. No.5,802,229, while a typical laser employable for the medical instrument20 is the Optima laser which will be sold by Ethicon Endo-Surgery inCincinnati, Ohio. The optical fiber 28 with the attached connector 18can be provided and sold separately from the source of light 22, as anoptical fiber assembly 29, as represented in FIG. 3 of the drawings.

A typical optical fiber 28 according to one embodiment of the presentinvention, including diffuser portion 19 and a proximallight-transmitting portion 34 is shown in FIG. 4. In alight-transmitting portion 23 of the optical fiber 28, a cladding 32 andthe proximal portion 34 of a sleeve 38 radially surround the proximalportion 30 of a core 31. The optical fiber 28 may also have a bufferlayer 42 arranged to extend circumferentially between the cladding 32and the sleeve 38. The material used to form the cladding 32 has anindex of refraction lower than the index of refraction of thematerial-used to create the core 31 so as to contain the light withinthe core 31. The core 31, in addition to its proximal portion 30,extends through a distal portion 36 to the distal end 52 thereof. Thedistal portion 36 of the core 31 which is employed to diffuse light, issurrounded by an optical coupling layer 40 and the distal portion 44 ofthe sleeve 38. There is no interruption, discontinuity, or weld joint onthe sleeve 38 inasmuch as the proximal portion 34 of the sleeve 38 andthe distal portion 44 of the sleeve 38 are two segments of onecontinuous unitarily constructed sleeve 38. The sleeve 38 can extenddistally past the distal end 52 of the core 31 and may be configured topenetrating tip 50. The sleeve 38, as mentioned, is constituted of onecontinuous piece, preferably consisting of perfluoroalkoxy impregnatedwith barium sulfate.

A material having an index of refraction higher than the index ofrefraction of the core 31 forms the optical coupling layer 40, whereinUV50 Adhesive, available from Chemence, Incorporated, in Alpharetta,Ga., can be used to produce the optical coupling layer 40.

A light-scattering component 48 which is filled with a light-scatteringmaterial and located on the distal face 52 of the core 31 can reflectlight back into the core 31 so as to provide a more even or uniformlight distribution, whereby alexandrite can be employed as thelight-scattering material for component 48. In addition to itslight-scattering properties, the material fluoresces in atemperature-dependent manner upon being stimulated by light, with thisproperty adapted to be used to measure temperature in tissue inproximity to the diffuser portion 19. The same adhesive which isemployed for the optical coupling layer 40 can suspend the alexandriteparticles therein and can serve as the base material for thelight-scattering component 48.

As illustrated in, respectively, FIGS. 4 and 7, utilizing thelight-scattering component 48, the sleeve 38 is shaped to extenddistally past the light-scattering component 48 and resultingly forms apointed penetrating tip 50.

During operation of the medical instrument 20, light generated by thesource of light energy 22 travels through the core 31 to the diffuserportion 19. There, in the embodiment of the invention illustrated inFIG. 4, light energy emerges from the core 31 to the optical couplinglayer 40 because of the optical coupling layer having a higher index ofrefraction. The distal portion 44 of the sleeve 38 which surrounds theoptical coupling layer 40, collects the light from the optical layer 40,employing the abrasions formed on the inner surface of the distalportion 44 of the sleeve 38. The sleeve 38 preferably uses bariumsulfate particles scattered within the sleeve 38 to direct light energyevenly outwards towards the tissue. Light energy reaching thelight-scattering component 48 is reflected back towards the core 31 bythe alexandrite particles in the light-scattering component 48.Moreover, the fluorescent properties of the alexandrite particles, whenstimulated by light energy of the proper wavelength, can determine thetemperature of surrounding tissues employing methods which are known inthe art. The penetrating tip 50 is capable of piercing tough tissue inorder to assist medical procedures.

The inventive sleeve 38 has no weld joints or discontinuities in theouter diameter extending from the proximal end of the penetrating tip 50to the connector 18 which conceivably tend to weaken the optical fiber28, or which may detrimentally catch or drag the optical fiber 28 so asto displace the latter while in use. When using the optical fiber 28,surgeons or medical practitioners often need to bend it to successfullylocate the fiber in the body of a patient. The optical fiber 28 and theassociated sleeve 38 can withstand more bending than optical fibers withsleeves which have weld lines or discontinuities formed in the outerdiameter thereof proximal to the penetrating tip 50.

Method of Forming the Optical Fiber

In order to produce an optical fiber according to the invention as shownin FIG. 4, there can be modified an optical fiber 28 with its associatedsleeve 38. First, a sleeve 38 is provided which is approximately as longas the optical fiber to be used, and preferably long enough to extendfrom the connector 18 (shown in FIG. 3) past the distal face 52 of thecore 31. Thereafter, the inner surface of the distal portion 34 of thesleeve 38 is abraded. Different methods can be used to abrade, texture,or roughen the inner surface, such as brushing with a small brush,roughening with a small tool, or pressing against a mandrel to mold inrough areas, can all be employed in order to create a rough innersurface. The roughening process can be implemented while the sleeve 38is a separate piece before its assembly with the other components of theoptical fiber 28, or it can be effected subsequent to assembly. In casethe roughening process is performed after assembling the sleeve to thefiber, the sleeve 38 is slid over the buffer layer 42 so as to extendthe sleeve 38 distally beyond the distal end of the buffer layer 42 andcore 31. Moving the sleeve 38 distally beyond the distal end of thebuffer layer 42 and core 31 will expose the interior of the sleeve 38 sothat it can be easily abraded.

After abrading, in order to prepare the optical fiber 28 for assembly,the distal portion 36 of the core 31 is exposed by stripping away thebuffer layer 42 and the surrounding cladding 32. Leaving the cladding 32so as to extend distally beyond the end of the buffer layer 42 in astepped manner, as shown in FIG. 4, reduces the formation of any stressconcentration points.

In order to make the light-scattering component 48, a mix of alexandriteparticles and uncured adhesive, preferably in a ratio of 2.5 to 1 ofalexandrite to adhesive by weight, is conveyed into a tube material usedfor annulus 46, and having an inner diameter which is equal to the outerdiameter of the core 19. The annulus material should be long enough toextend well beyond the end of the sleeve 38 upon assembly. The mix ofuncured light-scattering component material is an axial length ofannulus material 46 containing the light-scattering component 48, asshown in FIG. 5.

The sleeve 38 is then slid over the prepared core 31 and buffer layer 42until the sleeve 38 extends beyond the distal face 52 of the core 31.Uncured adhesive 53 is then applied to the empty volume or space left bythe buffer layer 42 and cladding 32 having been previously removed. Thesleeve 38 is moved so as to extend the core 31 slightly beyond the endof the sleeve 38, and the length of annulus material containing theuncured light-scattering component material is then fitted over the endof the exposed core 19. The light-scattering component material shouldabut the distal face 52 of the core 19 and a small length of annulusmaterial should surround the core 19 near its distal face 52. The core31, the light-scattering component material, and a length of annulusmaterial are then recessed or withdrawn into the sleeve 38, leaving alength of annulus material extending beyond the distal face 52 of thecore 31, and substantially the same distance beyond face 52 as sleeve38, illustrated in FIG. 6. In case no light-scattering component 48 isneeded, the length of annulus material without the light-scatteringcomponent 48 is positioned around the core 31 near its distal face 52.

In an optional step, there may be removed any air bubbles which may bepresent in the optical coupling layer 40. The distal end of the opticalfiber 28 with the distal face 52 of the core 31 is held down while beingheated to allow the adhesive that will form the optical coupling layer40 to flow towards the distal end under the effect of gravity. This stepwill assist in eliminating air from the optical coupling layer 40 inorder to allow it to transmit light from the core 31 more efficiently,whereby, for instance, heat can be applied with a heat gun.

With the annulus material in place, the adhesive and thelight-scattering component material are cured to form the opticalcoupling layer and light-scattering component 48 whereby pursuant to oneembodiment of the invention, the adhesive can be cured by means ofultraviolet light.

The penetrating tip 50 is formed by placing the distal end of theoptical fiber into a mold and heating it to melt and fuse the sleeve 38and the annulus 46 into one piece, producing the embodiment shown inFIG. 4, leaving a small air pocket 51 in conjunction with thelight-scattering component 48.

In one embodiment of the invention, both the annulus 46 and the sleeve38 are made of the same material and formed into one piece so that theannulus 46 becomes a part of the sleeve 38 once the parts are melted andfused. The annulus 46, as a portion of the sleeve 38, contacts the core31 at the distal portion 36 of the core. It also contacts and aligns thelight-scattering component 48 upon use of the light scattering component48. The penetrating tip 50 being formed on the optical fiber 28,referred to as tipping, completes the diffuser portion 19 on the opticalfiber 28.

Another method of forming an embodiment of the optical fiber pursuant tothe invention produces the configuration shown in FIG. 7. In order toproduce this embodiment, the cladding 32 and the buffer layer 42 arefirst stripped from the core 31, as described in the previous method.The distal portion 44 of the sleeve 38 is abraded as before. The sleeve38 is then displaced so as to extend past at least the distal face 52 ofthe core 31. Using an adhesive which is curable into an optical couplinglayer 40, the void left by the removed buffer layer 42 and cladding 32is then filled. If the light-scattering component 48 is used, thelight-scattering component 48 is pushed through the uncured adhesive tothe distal face 52 of the core 31. In order to close the end of sleeve38, the sleeve end is heated in a mold which forces the sleeve 38radially towards the core 31 to thereby form the embodiment shown inFIG. 7, with the sleeve 38 connecting the core 31 and thelight-scattering component 48, and air pocket 51 formed within tip 50.The adhesive is cured into the optical coupling layer 40, whereby in oneembodiment of the intention, ultraviolet light can be used to cure theadhesive.

It is readily apparent that equivalent structures may be substituted forthe structures illustrated and described herein and that the describedembodiments of the invention are not limited to those elucidated. As oneexample of an equivalent structure which may be used, the opticalcoupling layer 28 can comprise a substance filled with light-scatteringparticles, which if employed eliminates need to abrade the inner surfaceof the sleeve 38.

While the invention has been particularly shown and described withrespect to preferred embodiments thereof, it will be understood by thoseskilled in the art that the foregoing and other changes in form anddetails may be made therein without departing form the spirit and scopeof the invention.

What is claimed is:
 1. A medical instrument for the treatment of tissue,said medical instrument including a source of light energy; and aconnector removably attachable to said source of light energy; and anoptical fiber having a proximal end, connected to said connector, and adistal end positionable at a site of the treatment, said optical fibercomprising: a core having a distal portion and a distal face proximatesaid distal end of the optical fiber; an optical coupling layer radiallysurrounding said distal portion of said core; and a sleeve of unitaryconstruction radially surrounding said optical coupling layer extendingcontinuously and uninterrupted along the length of said optical fiberfrom said distal face of said core to said connector.
 2. The medicalinstrument according to claim 1, wherein said sleeve forms a penetratingtip distal to said distal face of said core.
 3. The medical instrumentaccording to claim 2, wherein said optical fiber further comprises alight-scattering component affixed to said distal face of said core. 4.An optical fiber assembly having a proximal end and a distal end, saidoptical fiber assembly comprising: a) a core having a distal portion anda distal face; b) an optical coupling layer radially surrounding saiddistal end of the optical fiber assembly core; c) a connector affixed atsaid proximal end of said optical fiber assembly; and d) a sleeveradially surrounding said optical coupling layer and extendingcontinuously and uninterruptedly from said distal face of said core tosaid connector.
 5. The optical fiber assembly according to claim 4,wherein said sleeve forms a penetrating tip distal to the distal face tosaid core.
 6. The optical fiber assembly according to claim 5,comprising a light-scattering component affixed to said distal face ofsaid core.
 7. The optical fiber assembly according to claim 4, whereinsaid sleeve is of a unitary, single-piece construction.
 8. A medicaldevice comprising: a source of laser light energy; an optical connectorremovably attachable to said source of light energy; and an opticalfiber having a proximal end associated with said connector and a distalend, wherein said optical fiber comprises a core having a distalportion, an optical coupling layer radially surrounding said distalportion of said core, and a sleeve of unitary construction radiallysurrounding said optical coupling layer, said sleeve comprising a tissuepenetrating tip distal of said core, and said sleeve extendingcontinuously and uninterrupted from said penetrating tip to said opticalconnector.
 9. An assembly for use in delivering light energy in amedical procedure, the assembly comprising: a light transmitting corehaving a proximal portion and a distal portion; an optical connector forcoupling said proximal portion of said core to a source of light; and anouter sleeve of unitary construction comprising a tissue penetratingtip, said tip disposed distal of said core, and wherein said sleeveextends from said penetrating tip to said optical connector in acontinuous, uninterrupted fashion.